1. Field of the Invention
The present invention generally relates to data base management systems and more particularly relates to enhancements for providing access to data base management systems via internet user terminals.
2. Description of the Prior Art
Data base management systems are well known in the data processing art. Such commercial systems have been in general use for more than 20 years. One of the most successful data base management systems is available from Unisys Corporation and is called the Classic MAPPER(copyright) data base management system. The Classic MAPPER system can be reviewed using the Classic MAPPER User""s Guide which may be obtained from Unisys Corporation.
The Classic MAPPER system, which runs on proprietary hardware also available from Unisys Corporation, provides a way for clients to partition data bases into structures called filing cabinets and drawers, as a way to offer a more tangible format. The Mapper data base manager utilizes various predefined high-level instructions whereby the data base user may manipulate the data base to generate human-readable data presentations called xe2x80x9creportsxe2x80x9d. The user is permitted to prepare lists of the various predefined high-level instructions into data base manager programs called xe2x80x9cMapper Runsxe2x80x9d:. Thus, users of the Classic MAPPER system may create, modify, and add to a given data base and also generate periodic and aperiodic reports using various Mapper Runs.
However, with the Classic MAPPER system, as well as with similar proprietary data base management systems, the user must interface with the data base using a terminal coupled directly to the proprietary system and must access and manipulate the data using the Mapper Run command language of Classic MAPPER. Ordinarily, that means that the user must either be co-located with the hardware which hosts the data base management system or must be coupled to that hardware through dedicated telephone, satellite, or other data links. Furthermore, the user usually needs to be schooled in the command language of Classic MAPPER (or other proprietary data base management system) to be capable of generating Mapper Runs.
Since the advent of large scale, dedicated, proprietary data base management systems, the internet or world wide web has come into being. Unlike closed proprietary data base management systems, the internet has become a world wide bulletin board, permitting all to achieve nearly equal access using a wide variety of hardware, software, and communication protocols. Even though some standardization has developed, one of the important characteristics of the world wide web is its ability to constantly accept new and emerging techniques within a global framework. Many current users of the internet have utilized several generations of hardware and software from a wide variety of suppliers from all over the world. It is not uncommon for current day young children to have ready access to the world wide web and to have substantial experience in data access using the internet.
Thus, the major advantage of the internet is its universality. Nearly anyone, anywhere can become a user. That means that virtually all persons are potentially internet users without the need for specialized training and/or proprietary hardware and software. One can readily see that providing access to a proprietary data base management system, such as Classic MAPPER, through the internet would yield an extremely inexpensive and universally available means for accessing the data which it contains and such access would be without the need for considerable specialized training.
There are several basic problems with permitting internet access to a proprietary data base. The first is a matter of security. Because the internet is basically a means to publish information, great care must be taken to avoid intentional or inadvertent access to certain data by unauthorized internet users. In practice this is substantially complicated by the need to provide various levels of authorization to internet users to take full advantage of the technique. For example, one might have a first level involving no special security features available to any internet user. A second level might be for specific customers, whereas a third level might be authorized only for employees. One or more fourth levels of security might be available for officers or others having specialized data access needs.
Existing data base managers have security systems, of course. However, because of the physical security with a proprietary system, a certain degree of security is inherent in the limited access. On the other hand, access via the internet is virtually unlimited which makes the security issue much more acute.
The second major problem is imposed by the internet protocol itself. One of the characteristics of the internet which makes it so universal is that any single transaction in HTML language combines a single transfer (or request) from a user coupled with a single response from the internet server. In general, there is no means for linking multiple transfers (or requests) and multiple responses. In this manner, the internet utilizes a transaction model which may be referred to as xe2x80x9cstatelessxe2x80x9d. This limitation ensures that the internet, its users, and its servers remain sufficiently independent during operation that no one entity or group of entities can unduly delay or xe2x80x9chang-upxe2x80x9d the communications system or any of its major components. Each transmissions results in a termination of the transaction. Thus, there is no general purpose means to link data from one internet transaction to another, even though in certain specialized applications limited amounts of data may be coupled using xe2x80x9ccookiesxe2x80x9d or via attaching data to a specific HTML screen.
However, some of the most powerful data base management functions or services of necessity rely on coupling data from one transaction to another in dialog fashion. In fact this linking is of the essence of Mapper Runs which assume change of state from one command language statement to the next. True statelessness from a first Mapper command to the next or subsequent Mapper command would preclude much of the power of Classic MAPPER (or any other modern data base management system) as a data base management tool and would eliminate data base management as we now know it.
It is readily appreciated that communication between the internet user terminal and the server hosting the Cool ICE data base management system is through the use of HTML display pages, whereas the internal communication within the server is not. A standard technique for identification of an object type within the HTML protocol is through the use of MIME type. This standard readily identifies the type of object (e.g., text, audio, video, graphics, etc.). However, the MIME type is typically not used with existing proprietary data base management systems and is not used at all with Classic MAPPER system. Therefore, a problem exists with the transfer of objects from the server to the internet terminal without the MIME type to identify the nature of the data.
The present invention overcomes the disadvantages of the prior art by providing a method of and apparatus for utilizing the power of a full featured data base management system by a user at a terminal coupled to the world wide web or internet. In order to permit any such access, the present invention must first provide a user interface, called a gateway, which translates transaction data transferred from the user over the internet in HTML format into a format from which data base management system commands and inputs may be generated. The gateway must also convert the data base management system responses and outputs into an HTML document for display on the user""s internet terminal. Thus, as a minimum, the gateway must make these format and protocol conversions. In the preferred embodiment, the gateway resides in the web server coupled to the user via the world wide web and coupled to proprietary data base management system.
To make access to a proprietary data base by internet users practical, a sophisticated security system is required to prevent intentional or inadvertent unauthorized accesses. As discussed above, such a security system should provide multiple levels of access to accommodate a variety of authorized user categories. In the preferred embodiment of the present invention, several levels of data classification are provided and several classes of users are defined. This permits certain levels of data to be accessed by one or more of the several classes of user. The security system may either reside in the web server containing the gateway or may be an existing component of the data base management system.
Whereas the gateway and the security system are the minimum necessary to permit the most rudimentary form of communication between the internet terminal of the user and the proprietary data base management system, as explained above, the internet is a xe2x80x9cstatelessxe2x80x9d communication system; the addition of the gateway and the security system do not change this statelessness. To unleash the real power of the data base management system, the communication protocol between the data base and the user requires functional interaction between the various data transfers.
The present invention adds state management to this environment. Instead of considering each transfer from the internet user coupled with the corresponding server response as an isolated transaction event as defined by the world wide web, one or more related service requests may be functionally associated in a service request sequence as defined by the data base management system into a dialog.
A repository is established to store the state of the service request sequence. As such, the repository can store intermediate requests and responses, as well as other data associated with the service request sequence. Thus, the repository buffers commands, data, and intermediate products utilized in formatting subsequent data base management service requests and in formatting subsequent HTML pages to be displayed to the user.
The transaction data in HTML format received by the server from the user, along with the state information stored in the repository, are processed by a service handler into a sequence of service requests in the command language of the data base management system. Sequencing and control of the data base management system is via an administration module.
Through the use of the repository to store the state of the service request sequence, the service handler to generate data base management command language, and the administration module, the world wide web user is capable of performing each and every data base management function available to any user, including a user from a proprietary terminal having a dedicated communication link which is co-located with the proprietary data base management system hardware and software. In addition, the data base management system user at the world wide web terminal is able to accomplish this in the HTML protocol, without extensive training concerning the command language of the data base management system.
The data transfers between the internet user terminals and the server is through HTML display pages. It is conventional to describe the data type of an HTML object through a standardized MIME type code. The preferred mode of the present invention preserves MIME type codes for objects received in HTML and synthesizes MIME type codes for objects created in other formats. The stored and/or synthesized MIME type code is transmitted along with HTML display pages in transfers from the server to an internet terminal.
In addition, the service handler facilities which maintain the MIME type code are also useful to store an expiration date, if any, associated with a particular object. Using the expiration date feature enables the server to automatically inhibit transmission of obsolete objects.